Abstract

The nonmonotonic level dependence of the intensity‐difference limens (DLs) for a broadband stimulus, the click [Raab and Taub, J. Acoust. Soc. Am. 46, 965–968 (1969)], can also be observed for a narrow‐band stimulus, a Gaussian‐enveloped 2‐kHz tone [Nizami etal., J. Acoust. Soc. Am. 107, 2820 (2000)]. Although the DLs for a 32‐ms tone‐pip (measured at plus‐or‐minus four standard deviations) follow the near‐miss to Webers Law, the DLs for a 4‐ms tone‐pip are higher, and peak mid‐level, at about 40 dB SL. The DLs are larger still, and the peak more profound, for an 8‐ms tone‐pip. Energy‐spectrum changes as duration changes, however, obscuring the source of the nonmonotonicity. Energy‐spectrum was therefore held constant by using a broadband‐noise carrier, while preserving the Gaussian envelope. DLs were obtained from two male and four female subjects (ages 18–40) having normal hearing thresholds. Noise‐pip levels ranged from 30 to 90 dB SPL at durations of 2, 4, 8, 16, and 32 ms. Although the across‐subject mean DLs for 32‐ and 16‐ms noise‐pips follow Weber’s law, the means for 8 ms are larger, and rise at mid‐level. The DLs grow as duration decreases from 8 to 4 to 2 ms, unlike the case for 2 kHz.